Method For Wireless System Selection Optimization

ABSTRACT

A method for improved system selection by wireless mobile devices in 3GPP networks is provided. Location data is retrieved by the wireless device to estimate an initial system on which the wireless mobile device will attempt initialization. Using the location data, an absolute radio frequency channel number (ARFCN) associated with the location data is determined from an ARFCN table stored in memory in the wireless mobile device. The wireless mobile device can then perform system selection using the determined ARFCN. A server generates and maintains the ARFCN table which is initially provided to the wireless mobile device at manufacturer, during provisioning or as an over-the-air update.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 12/357,771filed on Jan. 22, 2009, the entire disclosure of which is herebyincorporated by reference for all purposes.

TECHNICAL FIELD

The present disclosure relates to wireless mobile networks and inparticular to system selection by a mobile wireless device duringinitialization on a wireless network.

BACKGROUND

In 3GPP wireless network deployments, carriers or service providersdeploy multiple frequencies for distributing handling traffic capacity.During initialization, for example of a factory fresh device, orre-selection a wireless mobile device must scan a wide frequency rangeto determine the appropriate ARFCN (absolute radio frequency channelnumber) to enable access to the network as it has no knowledge yet as towhich frequency is to be utilized. An exhaustive search can take aconsiderable length of time because there are a large number ofpotential frequencies to be scanned delaying a user's initial access tothe system. The scan typically occurs during initial start-up or when a‘full reset’ type event occurs requiring the wireless mobile device tore-sync to the network. There is therefore a need for improved systemselection by wireless mobile devices that reduces system access time.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present disclosure will becomeapparent from the following detailed description, taken in combinationwith the appended drawings, in which:

FIG. 1 shows a block diagram of a wireless mobile device;

FIG. 2 shows a system diagram of server based system selectionoptimization;

FIG. 3 shows a method of ARFCN selection in a wireless mobile deviceusing internal location data;

FIG. 4 shows a method of ARFCN selection in a wireless mobile deviceusing a GPS location data; and

FIG. 5 shows a method of generating and maintaining ARFCN tables at aserver.

It will be noted that throughout the appended drawings, like featuresare identified by like reference numerals.

DETAILED DESCRIPTION

In accordance with an aspect of the present disclosure there is provideda method of system selection in a mobile wireless device, the mobilewireless device operable on a 3GPP wireless network. An absolute radiofrequency channel number (ARFCN) table is stored in a memory of thewireless mobile device. Location data associated with the wirelessdevice is then retrieved prior to accessing the wireless network. Anabsolute radio frequency channel number (ARFCN) associated with theretrieved location data is determined from the ARFCN table stored inmemory and system selection is then performed using the determinedARFCN.

In accordance with another aspect another aspect of the presentdisclosure there is provided a wireless mobile device in a 3GPP wirelessnetwork. The wireless mobile device comprises a memory and a controlprocessor for executing instructions in the memory. The instructionscomprising retrieving location data associated with the wireless device;determining an absolute radio frequency channel number (ARFCN)associated with the location data from an ARFCN table stored in memoryin the wireless mobile device; and performing system selection using thedetermined ARFCN.

In accordance with yet another aspect of the present disclosure there isalso provided a method on a server of enabling system selection by aplurality of wireless mobile devices in a 3GPP wireless network. Anabsolute radio frequency channel number (ARFCN) table is generatedcomprising location data and one or more associated ARFCNs. The ARFCNtable is sent to each of the plurality of wireless mobile deviceswherein each of the plurality of wireless mobile devices utilizes aselected ARFCN associated with determined location data when attemptingto initialize on the wireless network.

In accordance with still yet another aspect of the present disclosurethere is provided a server for enabling system selection by a pluralityof wireless mobile devices in a 3GPP wireless network. The servercomprising a memory and a processor for executing instructions in thememory. An absolute radio frequency channel number (ARFCN) table isgenerated comprising location data and one or more associated ARFCNs.The ARFCN table is sent to each of the plurality of wireless mobiledevices wherein each of the plurality of wireless mobile devicesutilizes a selected ARFCN associated with determined location data whenattempting to initialize on the wireless network.

3GPP wireless networks are uniquely identified by a specific MobileCountry Code (MCC) and a specific Mobile Network Code (MNC). Wirelessmobile devices are provisioned by carriers (service providers) to have apreferred MCC and MNC. In addition, when the carrier has roamingagreements a preferred list may be stored in a Subscriber IdentityModule (SIM), a Universal SIM (USIM), or some other non-volatile memorymodule resident within the wireless mobile device. The MCC and MNC areutilized by the wireless mobile device to determine which system ornetwork it should be operating on. However, the device must still scanthe available frequencies to determine the appropriate ARFCN (absoluteradio frequency channel number) to access the system. As wireless mobiledevices have no notion of which ARFCNs to first scan, the scan isexhaustive which can take a very long time.

To accelerate the ability of a wireless mobile device to access a systemduring initialization or re-selection, a table or service bookidentifying known ARFCNs associated with systems is provided. Thewireless mobile device can then initiate scanning to access the systemusing a known ARFCN associated with the likely system rather than havingto scan all possible ARFCNs. The table can be provisioned duringmanufacture or delivered to the wireless mobile device upon registrationin the field over-the-air for storage with the device. The tableidentifies routing area identifier (RAI) defining a MCC.MNC and anassociated ARFCN for the particular network. When the mobile wirelessdevice must acquire a system, location related data such as the MCC.MNCassociated with the device can be determined from information stored onthe SIM card in the device. Alternatively, location data can be basedupon proprietary handset branding data associated with the operatingsoftware load in the device stored in flash memory 144. This informationis then used to look up an ARFCN associated with the RAI combinationenabling the device to tune directly to the ARFCN reducing requiredsearch time. The RAI in the table may include LAC (location area code)and RAC (routing area code) information providing additional granularityif different ARFCN's are used throughout the system. Alternatively, aGPS (Global Positioning System) receiver integrated in the device may beused to determine a position of the device prior to initializationenabling a location look-up in the ARFCN table. By providing an ARFCN tothe device prior to network access initial scans are much quicker thusdecreasing the effective “time to find first channel” when powering onfor the first time and enhancing the users first use experience.Further, even subsequent to a successful network access, the handsetsystem selection may be improved with prior knowledge of ARFCNs in itscurrent location. Examples are when a handset needs to rescan, forexample, within RF coverage holes, or when a users manual wishes torescan for frequencies.

The ARFCN table may be generated based upon information provideddirectly by carriers and stored on a server connected to the network oraccessible during manufacturing or provided by a protocol where handsetsalready in field report in to a central server the ARFCNs that are beingseen. The table may be retrieved from the server and provided to amobile device at manufacture or during initial programming. In additionthe server may be connected to one or more networks enabling updates tothe ARFCN table to be received from carrier or from devices on thenetworks to update ARFCN table information. The updated ARFCN tables canthen be provided to devices as required.

FIG. 1 is a block diagram of a wireless mobile device 100 incorporatinga communication subsystem having both a receiver 112 and a transmitter114, as well as associated components such as one or more embedded orinternal antenna elements 116 and 118, local oscillators (L0s) 113, anda processing module such as a digital signal processor (DSP) 120. Theparticular design of the communication subsystem will be dependent uponthe communication network in which the device is intended to operatesuch as in a GSM, EDGE, UMTS, or 3GPP LTE networks.

The wireless mobile device 100 performs synchronization, registration oractivation procedures by sending and receiving communication signalsover the network 102. Signals received by antenna 116 throughcommunication network 100 are input to receiver 112, which may performsuch common receiver functions as signal amplification, frequency downconversion, filtering, channel selection and the like, and in theexample system shown in FIG. 1, analog to digital (ND) conversion. NDconversion of a received signal allows more complex communicationfunctions such as demodulation, decoding and synchronization to beperformed in the DSP 120.

In a similar manner, signals to be transmitted are processed, includingmodulation and encoding for example, by DSP 120 and input to transmitter114 for digital to analog conversion, frequency up conversion,filtering, amplification and transmission over the communication network102 via antenna 118. DSP 120 not only processes communication signals,but also provides for receiver and transmitter control. For example, thegains applied to communication signals in receiver 112 and transmitter114 may be adaptively controlled through automatic gain controlalgorithms implemented in DSP 120.

Wireless mobile device 100 preferably includes a radio processor 111 anda control processor 180 which together control the overall operation ofthe device. DSP 120 is located on radio processor 111. Communicationfunctions are performed through radio processor 111.

Radio processor 111 interacts with receiver 112 and transmitter 114, andfurther with flash memory 162, random access memory (RAM) 160, thesubscriber identity module 164, a headset 168, a speaker 170, and amicrophone 172.

Control processor 180 interacts with further device subsystems such asthe display 122, flash memory 144, random access memory (RAM) 136,auxiliary input/output (I/O) subsystems 128, serial port 130, keyboard132, other communications 138, GPS receiver 140 and other devicesubsystems generally designated as 142.

Some of the subsystems shown in FIG. 1 perform communication-relatedfunctions, whereas other subsystems may provide “resident” or on-devicefunctions. Notably, some subsystems, such as keyboard 132 and display122, for example, may be used for both communication-related functions,such as entering a text message for transmission over a communicationnetwork, and device-resident functions such as a calculator or tasklist.

Software used by radio processor 111 and control processor 180 ispreferably stored in a persistent store such as flash memory 144 and162, which may instead be a read-only memory (ROM) or similar storageelement (not shown). Those skilled in the art will appreciate that theoperating system, specific device applications, or parts thereof, may betemporarily loaded into a volatile memory such as RAM 136 and RAM 160.Received communication signals may also be stored in RAM 136.

As shown, flash memory 144 can be segregated into different areas forcomputer programs 146, device state 148, address book 150, otherpersonal information management (PIM) 152 and other functionality suchas the ARFCN table generally designated as 154. These different storagetypes indicate that each program can allocate a portion of flash memory144 for their own data storage requirements. Control processor 180, inaddition to its operating system functions, preferably enables executionof software applications on the mobile station.

For voice communications, overall operation of wireless mobile device100 is similar, except that received signals would preferably be outputto the speaker 170 or headset 168 and signals for transmission would begenerated by the microphone 172. Alternative voice or audio I/Osubsystems, such as a voice message recording subsystem, may also beimplemented on mobile station 102.

Serial port 130 in FIG. 1 would normally be implemented in a personaldigital assistant (PDA)-type wireless mobile device for whichsynchronization with a user's desktop computer (not shown) may bedesirable, but is an optional device component. Such a port 130 wouldenable a user to set preferences through an external device or softwareapplication and would extend the capabilities of wireless mobile device100 by providing for information or software downloads to wirelessmobile device 100 other than through a wireless communication network.The alternate download path may for example be used to load anencryption key onto the device through a direct and thus reliable andtrusted connection to thereby enable secure device communication.

Other device subsystems 142, such as a short-range communicationssubsystem, is a further optional component which may provide forcommunication between wireless mobile device 100 and different systemsor devices, which need not necessarily be similar devices. For example,the subsystem 142 may include an infrared device and associated circuitsand components or a Bluetooth™ communication module to provide forcommunication with similarly enabled systems and devices.

FIG. 2 shows a system diagram of server based system selectionoptimization. Server 150 may be coupled to storage device 156. Thestorage device 156 stores ARFCN table 160 and computer executable codefor generating the ARFCN table and sending and receiving updates. TheARFCN table comprises an entry for every RAI (routing area identifier)162. Depending on the granularity required, the RAI may be solely basedupon MCC.MNC or be further resolved by MCC.MNC.LAC.RAC, where LAC(location area code) and RAC (routing area code) are used if the mobiledevice has data associated with the last LAC.RAC used while accessingthe network. One or more ARFCNs 164 can then be associated with each RAIentry. The ARFCN may be provided by a carrier or by mobile wirelessdevice provided updates as discussed in connection with FIG. 5. Ifdevice updates to the ARFCN table are enabled, a suspension tag 166 canalso be identified for each entry. The suspension tag 166 identifies adate at which the identified ARFCN is deemed be expired and will beremoved form the table unless an update is received from a device on thenetwork identifying the ARFCN as active. The wireless mobile device usesthe tag as a trigger to only send an update only when necessary. TheARFCN table may also include GPS coordinates, providing latitude andlongitude, (not shown) associated with each RAI entry if a GPS receivercoupled to device is used during initialization or re-acquisition. TheGPS coordinates in the ARFCN may be based on a range defining a servicearea for the RAI and ARFCN.

Each system 110 and 120 has a unique MCC.MNC. Base stations 102, 106 and122 can then be assigned to a unique MCC.MNC.LAC.RAC if different AFRCNare utilized within the same MCC.MNC network. The wireless network 110and 120 are in communication with server 150. The server 150 may be acentral server or be resident on each carrier's network. The server 150contains software stored in memory 154 and executed by one or morecentral processing units 152 for generating and sending (or pushing)ARFCN tables to devices in addition to receiving updates from wirelessdevices accessing the system. During manufacture or initial programmingby the carrier a wireless mobile device 116 receives the ARFCN table orservice book which would be stored within non-volatile memory 144 of thedevice.

In additional to directly editing the ARFCN table, updates may beprovided from devices operating on the networks once initialized. Forexample, device 112 can provide an update to the server 150 identifyingan ARFCN change associated either with the carrier's wireless network110 MCC.MNC or even the BTS 106 MCC.MNC.LAC.RAC. The updates areprovided once the device is operating on the network and has determinedthat the ARFCN used for network access does not match the ARFCNidentified in the ARFCN table. Updates to the ARFCN table can then bepushed to devices on the network such as devices 100 and 114 at periodicintervals to unsure the most current information is available.

FIG. 3 shows a method of ARFCN selection using a network identifierretrieved from the mobile wireless device 100. This method is distinctin that it bootstraps the handset with information on the assumptionthat most times, the initial use will be in the home MCC.MNC onparticular ARFCNs. The wireless mobile device 100 receives an ARFCNtable either during manufacture or initial programming or provisioning.The ARFCN is stored 302 in memory of the mobile wireless device. Whenthe device powers up, prior to acquiring a network and registering onthe network, the device retrieves location data to determine or infer304 what is the primary carrier associated with the device either byretrieving MCC.MNC information from the SIM or by accessing proprietaryhandset branding The handset may use and empty MRU (most recently usedAFRCN) as a trigger to determine its likely location via carrierbranding and thereby make use of the ARFCN table. information whichidentifies an associated MCC.MNC. A look-up 306 in the ARFCN table isperformed to determine the associated ARFCN for the MCC.MNC. Systemselection is then performed 308 using the selected ARFCN frequency or aseries of applicable ARFCNs. If the ARFCN used is not successful ataccessing the system, NO at 310, a periodic update can then be sent 312over the wireless network to server 150 providing details regarding theMCC.MNC and the ARFCN used to access the system. If the system isaccessed using the ARFCN, YES at 310, it can then be determined if thesuspension tag associated with the ARFCN has expired 314. The suspensiontag expiry is defined in relation to a date or time interval associatedwith the RAI entry in the ARFCN table 160 assigned by the server uponcreation of the table. If the tag has expired, YES at 314, a periodicupdate can be sent to server 150 identifying that the ARFCN is stillactive 316. The suspension tag can then be increased at the next ARFCNupdate. If the suspension tag has not expired, NO at 314, initializationor re-acquisition is completed at 318. At 320 the device may thenreceive an updated ARFCN table for use during future re-initializations.

FIG. 4 shows a method of system selection using location data such asGPS position data. The wireless mobile device 100 receives an ARFCNtable, either during manufacture or initial programming or provisioning.The ARFCN is then stored 400 in memory of the mobile wireless device.The mobile wireless device retrieves GPS location information 402 froman internal GPS receiver or from an external GPS source coupled to thedevice prior to system access during power up or re-initialization. Asthe device is not on the network, network assisted GPS is not utilized.A look-up 404 in the ARFCN table is performed to determine theassociated ARFCN for the associated location. System selection is thenperformed 406 using the selected ARFCN frequency. If the ARFCN used isnot successful at accessing the system, NO at 408, a periodic update canthen be sent 410 to server 150 providing details regarding the GPSlocation and the ARFCN used to access the system after successful systemacquisition. If the system is accessed using the ARFCN, YES at 408, itcan then be determined if the suspension tag associated with the ARFCNhas expired 412. If the tag has expired, YES at 412, a periodic updatecan be sent to server 150 identifying that the ARFCN is still active414. The suspension tag can then be increased at the next ARFCN update.If the suspension tag has not expired, NO at 412, initialization orre-acquisition is completed at 416. At 418 the device may then receivean updated ARFCN table for use during future re-initializations.

FIG. 5 shows a method of maintaining ARFCN tables at a server. Theserver may be used to provide ARFCN a stand alone server or integratedas software with other servers during the manufacturing processes orcoupled to the carrier wireless network to provide updates. An initialARFCN table is generated 502 for loading to the wireless mobile devices.The ARFCN table may be populated by either information provided bycarriers or populated based upon data acquired from devices on theassociated networks via update messages. The ARFCN table is then sent tomobiles devices either during manufacture or initial programming 504.Alternatively the table may be provided upon registration of thewireless mobile device with the server over the air and pushed to thedevice. If the mobile wireless device 100 software is configured to sendupdates, the server receives updates from information obtained bydevices accessing systems or directly provided by carriers 506. If a newARFCN is identified in the update, YES at 508, the ARFCN for theassociated RAI is replaced 510. If the ARFCN is not new, NO at 508, itis then determined if the update is associated with an existing ARFCNthat has an expired suspension tag. If the suspension tag is expired inthe update, YES at 512, the suspension tag is updated to a new value514. If the tag in the updated is not expired, NO at 512, expired ARFCNscan then be removed from the table periodically 516 based upon apre-defined time interval after the suspension tag expiry. The updatedtable can then be sent to devices 518 or provided for upload to newdevices during manufacturing or provisioning.

While a particular embodiment of the present method for providingwireless system selection optimization has been described herein, itwill be appreciated by those skilled in the art that changes andmodifications may be made thereto without departing from the disclosurein its broadest aspects and as set forth in the following claims.

What is claimed:
 1. A method of system selection in a wireless mobiledevice, the wireless mobile device operable on a 3GPP wireless network,the method comprising: storing an absolute radio frequency channelnumber (ARFCN) table in a memory of the wireless mobile device;retrieving location data associated with the wireless mobile deviceprior to accessing the wireless network; determining an ARFCN associatedwith the retrieved location data from the ARFCN table stored in memory;performing a system selection using the determined ARFCN; determiningthat the system selection using the determined ARFCN is successful andthat the ARFCN has not expired; and sending an indication to a remoteserver maintaining a remote ARFCN table that the ARFCN is in use,wherein the ARFCN table comprises a routing area identifier (RAI); andwherein the RAI associates with the determined ARFCN.
 2. The method ofclaim 1 wherein the ARFCN table is stored in the memory of the wirelessmobile device at the time of manufacture.
 3. The method of claim 2wherein the RAI comprises a mobile country code (MCC) and mobile networkcode (MNC).
 4. The method of claim 3 wherein the RAI further comprises alocation area code (LAC) and routing area code (RAC).
 5. The method ofclaim 4 wherein the retrieved location data is a GPS location retrievedfrom a GPS receiver coupled to the wireless mobile device, and thelocation data of the ARFCN table comprises GPS location data associatedwith the RAI.
 6. The method of claim 3 wherein the retrieved locationdata is inferred based on a MCC.MNC retrieved from a subscriber identitymodule (SIM).
 7. The method of claim 3 wherein the retrieved locationdata is inferred based upon branding information associated with theoperating software load of wireless mobile device to determine acorresponding MCC.MNC.
 8. The method of claim 3 further comprisingsending an update to a server coupled to the wireless network, theupdate identifying an ARFCN not present in the ARFCN table on which thewireless mobile device successfully initialized and also identifyinglocation data of the wireless mobile device.
 9. The method of claim 2further comprising receiving an updated ARFCN table over-the-air.
 10. Awireless mobile device in a 3GPP wireless network, the wireless mobiledevice comprising: a memory comprising an absolute radio frequencychannel number (ARFCN) table; and a control processor for executinginstructions in the memory comprising: retrieving location dataassociated with the wireless mobile device; determining from the ARFCNtable an ARFCN associated with the location data; performing a systemselection using the determined ARFCN; determining that the systemselection using the determined ARFCN is successful and that the ARFCNhas not expired; and sending an indication to a remote servermaintaining a remote ARFCN table that the ARFCN is in use, wherein theARFCN table comprises a routing area identifier (RAI); and wherein theRAI associates with the determined ARFCN.
 11. A method on a server ofenabling system selection by a plurality of wireless mobile devices in a3GPP wireless network, the method comprising: generating an absoluteradio frequency channel number (ARFCN) table comprising location dataand one or more associated ARFCNs; sending the ARFCN table to each ofthe plurality of wireless mobile devices, wherein each of the pluralityof wireless mobile devices utilizes a selected ARFCN associated withdetermined location data when attempting to initialize on the wirelessnetwork; receiving an indication from a wireless mobile device that anARFCN in the ARFCN table is in use, when the wireless mobile devicesuccessfully initializes on the wireless network using the ARFCNprovided that the ARFCN is not expired; and updating an entry associatedwith the ARFCN based on the received indication.
 12. The method of claim11 wherein the location data is associated with routing area identifiers(RAIs) comprising a mobile country code (MCC) and mobile network code(MNC).
 13. The method of claim 11 further comprising: receiving updatesfrom the plurality of wireless mobile devices through the wirelessnetwork, the updates providing information for updating new or existingARFCNs associated with a particular RAI in the ARFCN table; updatingentries in the ARFCN table based upon the updates received from theplurality of wireless mobile devices; and sending the updated ARFCN tothe plurality of wireless mobile devices.
 14. The method of claim 13further comprising periodically removing ARFCN entries which haveexpired.
 15. The method of claim 13 wherein the ARFCN table contains GPSlocation data associated with the RAI and the RAI further comprises alocation area code (LAC) and routing area code (RAC).
 16. The method ofclaim 13 wherein the ARFCN table is sent to each of the plurality ofwireless mobile devices during handset manufacture.
 17. A server forenabling system selection by a plurality of wireless mobile devices in a3GPP wireless network, the server comprising: a memory; and a processorfor executing instructions in the memory that cause the server to:generate an absolute radio frequency channel number (ARFCN) tablecomprising location data and one or more associated ARFCNs; send theARFCN table to each of the plurality of wireless mobile devices whereineach of the plurality of wireless mobile devices utilizes a selectedARFCN associated with determined location data when attempting toinitialize on the wireless network; receive an indication from awireless mobile device that an ARFCN in the ARFCN table is in use, whenthe wireless mobile device successfully initializes on the wirelessnetwork using the ARFCN; and update the ARFCN table based on thereceived indication.
 18. The server of claim 17, wherein theinstructions further cause the server to: receive updates from theplurality of wireless mobile devices through the wireless network, theupdates providing information for updating new or existing ARFCNsassociated with a particular RAI in the ARFCN table; update entries inthe ARFCN table based upon the updates received from the plurality ofwireless mobile devices; and send the updated ARFCN to the plurality ofwireless mobile devices.
 19. The server of claim 17 wherein theinstructions further cause the server to periodically remove ARFCNentries which have expired.
 20. The server of claim 17 wherein the ARFCNtable contains GPS location data associated with the RAI and the RAIfurther comprises a location area code (LAC) and routing area code(RAC).